PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 217 



Occurrence of the pentacrinoid young. A.S yet the pentacrinoid young of the rosy 

 feather star have only been reported from a portion of the localities from which the 

 adults are known. 



They are recorded from the Orkneys (Busch, 1851); the east coast of Ireland 

 (Forbes, 1841); Belfast (Sars, 1868); Dublin Bay and off Ireland's Eye (Forbes, 1841, 

 on information from Messrs. R. Ball and Wm. Thompson) ; Cove of Cork (J. V. Thomp- 

 son, 1827); Firth of Clyde (Sars, 1868); off the north end of the Little Cumbrae, 9-18 

 meters (Grieve, 1868); Millport (Dendy, 1886); Lamlash Bay, Arran (Wyville Thom- 

 son, 1S6.5; W. B. Carpenter, 1866; Herdman, 1884); off Port Erin, Isle of Man, in 18- 

 37 meters (Herdman, 1881, 1886); near Rhoscolyn beacon (Herdman, 1891); Ilfra- 

 combe (W. B. Carpenter, 1866) ; Cornwall (Peach, 1864) ; Torbay, 22 meters (Hughes, 

 1873) ; off Berry Head, about 22 meters (Lang, 1877; Hunt, 1876) ; near Thatcher Rock 

 (Hunt, 1876); Petit Tor, 7 meters (Allman, 1863, 1864); Salcombe estuary, in shallow 

 water (Stebbing, 1876); Plymouth (Garstang, 1894; Pace, 1904); Jersey (Hornell, 

 1895; Sharp, 1908); and Roscoff (Lacaze-Duthiers, 1869, 1870; Perrier, 1873, 1886; 

 Pruvot, 1897). 



In the Orkneys Busch (1851) first found the larvae in the last days of July, and 

 at Cork J. V. Thompson (1835) found the eggs first in July. 



Mr. Elmhirst has written me that at Millport the gonads are ripe in June and July, 

 and (lie pentacrinoid stage occurs in August, September, and October. In these three 

 months young are found with an arm length of from 13 to 25 mm.; in December and 

 January the arm length is about 38 mm., in March 50 mm. and in May 75 mm., the 

 individuals becoming mature 100-mm. specimens in the summer. 



At Millport Dendy (1886) found that the height of the breeding season appeared 

 to be in July, and at Lamlash Bay Sir Wyville Thomson (1865) found that the spawn- 

 ing season commences at the end of May or the beginning of June. 



The best idea of the occurrence of pentacrinoids in Lamlash Bay is gained from 

 the following observations by Sir William Herdman and Dr. W. B. Carpenter. 



Herdman wrote (1884) that he was somewhat surprised in the summer of 1884 

 at finding - 1 iifnlon bifida in the pentacrinoid stage readily obtainable in Lamlash Bay 

 up to the end of September. The adults are abundant here, and young specimens 

 in the pentacrinoid stage are common on Laminaria in the earlier part of the summer; 

 but he had always found the pentacrinoids rare or absent during August, and certainly 

 never before found one in September. He found that Sir Wyville Thomson stated 

 that the ova are mature toward the end of May or the beginning of June, and that, 

 although the time spent in the larval stages may be to a certain extent shortened or 

 prolonged by surrounding conditions, the disengagement from the stalk constantly 

 occurs between the middle of August and the middle of September. From this one 

 would not expect to find any specimens in the pentacrinoid stage after the middle of 

 September. In 1884, however, while dredging chiefly in the southern part of the bay 

 near King's Cross Point, he obtained young stalked Antedons nearly every day between 

 September 15 and 25. He generally got one, two, or three specimens in a forenoon's 

 dredging (usually four or five hauls of the dredge). On September 27, the last day 

 he dredged, he found on some Fucus brought up from 11 to 13 meters at the south 

 entrance to the bay upwards of twenty specimens of pentacrinoids of all sizes from 

 3 up to 10 mm. in length of stalk. The last were evidently just ready to be set free, 

 and in fact several of them became disengaged from their stalks while he was watching 



